Clare Boothe Luce, 84, a former U.S. representative, playwright, ambassador to Italy, managing editor of Vanity Fair magazine and the widow of the founder and editor-in-chief of Time magazine, Henry R. Luce, died of cancer yesterday at her home in Washington.

Mrs. Luce was probably one of the half-dozen best known American women of this century, and during the 1940s and 1950s she was regularly at or near the top of such published lists as "most admired," "most glamorous" and "best-dressed" women in the world.

During their 32-year marriage, the Luces were the nation's premier media couple, and it was Mrs. Luce, early in their acquaintanceship, who suggested to her future husband that he publish a picture magazine called Life, which he began in 1936.

She was extraordinarily articulate with a nimble wit that made her preeminent at verbal one-upmanship. "I have seldom seen anyone hit a wisecrack past her," observed an old friend, Wilfrid Sheed, in a 1982 reminiscence, "Clare Boothe Luce." She was said to have coined the phrase "stuffed shirt," and other colloquialisms, and she could be eloquently harsh on those she didn't like. She once described Harold Ickes, President Roosevelt's secretary of the interior, as a "prodigious bureaucrat," with "the soul of a meat ax and the mind of a commissar."

Mrs. Luce was stunningly beautiful. Washington public relations executive Robert Gray said she was "drop-dead gorgeous" when she was a younger woman. William F. Buckley Jr. called her "God's definitive putdown to male chauvinism."

She was managing editor of Vanity Fair at the age of 30. As a playwright she had three solid Broadway hits before she was 40, "Margin for Error," "Kiss the Boys Goodbye," and "The Women," a scathing comedy about husband stealing, which MGM made into a highly successful movie in 1939. She traveled in Europe during the early months of World War II, returned to the United States and wrote a book, "Europe in the Spring," a satirical political analysis. Walter Lippmann called it the best book he'd read about people and conditions in Europe in 1940.

Later she was a war correspondent for Life in Europe and Asia, served as a Republican member of the House of Representatives from Connecticut from 1943 to 1947, and was President Eisenhower's ambassador to Italy from 1953 to 1957.

When she was in her fifties she took up skin-diving, and she wrote a series of articles for Sports Illustrated about what she found on the ocean floor while diving near the Bahamas.

She and her husband experimented briefly with the drug LSD during the 1960s.

Mrs. Luce had been on speaking terms with every president since Woodrow Wilson, and in the later decades of her life she became a forceful spokeswoman for conservative Republicanism. She was once a confidante of Bernard Baruch, the financier and adviser to presidents. She served on the Foreign Intelligence Advisory Board for Presidents Nixon, Ford and Reagan.

Ann Clare Boothe was born in New York City on April 10, 1903. Her parents separated when she was a child, and her father's financial contributions to the family were intermittent at best. They lived in a tenement where baths were taken in a sink in a kitchen smelling of cooked cabbage, and her mother worked as a sales clerk to help support her and an older brother.

Schooling tended to be sporadic, but the future Mrs. Luce was a voracious reader. Somehow her mother managed to take her to Paris for a year just before the beginning of World War I, and she spent the time learning French, visiting museums and reading.

Her mother later married a Greenwich, Conn., physician who sent her to two finishing schools in New York. She had no formal education beyond that, but she nevertheless managed to acquire a vast and impressive knowledge of a variety of subjects, especially art and literature.

In 1923 she married George Brokaw of New York and Newport, R.I., the heir to a garment business fortune who was 23 years older than she. He became the father of her only child, Ann Clare Brokaw. Their marriage ended in divorce after six years.

Soon afterward, Mrs. Luce's first book "Stuffed Shirts," a collection of short stories satirizing 1920s high society, was published. She was 26 at the time.

She joined the staff at Vogue magazine in 1930 as a writer of picture captions, was later made associate editor, then transferred to Vanity Fair where in 1933 she was made managing editor. A year later she left to write full time, and eventually seven of her plays were produced, most of them in the late 1930s.

She married Henry Luce in 1935 after he was divorced from his first wife. According to her friend Wilfrid Sheed, he proposed on their third meeting after they had discussed her ideas for Life with the announcement, "I don't want any more babies, but if you'll marry me, I'll start your magazine."

World War II and her husband's preoccupation with national and global politics interrupted her career as a playwright. They had dinner one night with Wendell Wilkie, the 1940 Republican presidential candidate, who captured the GOP nomination with the strong backing of the Luce publications. Mrs. Luce subsequently made several speeches on his behalf. It was her first real taste of participatory partisan politics. She liked it and discovered that she was good at it.

Early in 1942 she made a 75,000-mile sweep through Africa and Asia, reporting and writing about the war for Life. Then she went back to the Luce country home in southwestern Connecticut and, at the urging of friends, ran for the House of Representatives.

Her district included not only such New York City suburbs as Greenwich, but also working-class towns such as Danbury. There were more of the latter, and a majority of the voters were Democrats. Nevertheless, Mrs. Luce won narrowly in 1942 and 1944.

As a famous playwright and author, war correspondent and the wife of the editor-in-chief of Time magazine, she already had a national constituency when she arrived in Washington, and she attracted an extraordinary level of attention from the media. Time magazine itself, however, seemed to go to extraordinary lengths to avoid publishing her name.

Her first speech on the floor of the House in 1943 drew widespread coverage when she attacked Vice President Henry A. Wallace's plans for an international freedom of the skies aviation policy. "What Mr. Wallace calls his global thinking," declared Mrs. Luce, was in fact, "globaloney."

In 1944 she was keynote speaker and the first woman ever to address the Republican National Convention.

She toured the European battlefronts during the final years of the war and was said to have been able to ride over dusty roads in a jeep for hours, then step out with her hair neatly combed and in place and her clothes freshly pressed. She fired a howitzer shell against a German position in France. In 1945 she was part of a congressional delegation that visited the Buchenwald concentration camp and saw its victims' corpses stacked like cordwood.

Mrs. Luce was also one of the first to warn about Soviet dominance of Eastern Europe and the difficulties that such a situation posed for the United States, a stand that did her no harm among the several ethnic communities of her congressional district.

Then, in 1946, she announced she would not seek a third term in Congress. Her daughter Ann, a student at Stanford University, had been killed in a traffic accident in January 1944, and Mrs. Luce had joined the Roman Catholic Church in a search for spiritual strength to cope with the death of her only child.

"Connecticut has a large Catholic population," she said. "I would not care to have it said I joined the church to get votes." Like everything else Mrs. Luce did, her conversion to Catholicism drew a fair amount of publicity. She took her basic instruction in the articles of faith of the church from Archbishop Fulton J. Sheen, and she later wrote a three-part series of articles for McCall's magazine on her religious conversion.

But she did not drop out of politics.

She addressed the 1948 Republican National Convention in Philadelphia, attacking the Democrats as a party that "cannot win elections except in a climate of crisis," and thus "have a vested interest in depression at home and war abroad."

Four years later she campaigned aggressively for Dwight D. Eisenhower for president, making 47 radio and television speeches on his behalf. He named her U.S. ambassador in Rome in the first year of his administration.

In that role Mrs. Luce presided over a substantial increase in U.S. economic and military assistance to a nation that was one of the key elements in the NATO-backed alliance against post World War II communist expansion in Europe. She helped settle a delicate jurisdictional dispute between Italy and Yugoslavia over the city of Trieste. She was a prime target of attacks from the Italian communists, but also was immensely popular with the Italian people.

Her husband was said to have been proud and delighted with his wife's performace as ambassador, and during her years in Italy spent a part of each year at the ambassador's villa in Rome. Time magazine prepared a cover story on her in 1954, but Luce vetoed the idea, fearing it would lead to charges of nepotism. In 1957, Mrs. Luce resigned as ambassador after particles of arsenic contained in the paint on the ceilings at the villa caused her to become ill with arsenic poisoning, another incident that attracted worldwide publicity.

Eisenhower nominated her for ambassador to Brazil two years later, but she declined to assume the post after a bitter dispute with Sen. Wayne Morse (D-Ore.) during her Senate confirmation. Morse said that Mrs. Luce was unfit for the job, contending that she had slandered President Franklin D. Roosevelt by declaring in a 1944 campaign speech that "he lied us into war."

After the Senate approved her nomination 79 to 11, Mrs. Luce commented that her troubles "began when Sen. Wayne Morse was kicked in the head by a horse." (Morse had suffered a broken jaw when he was kicked by a mare at a 1951 horse show at Orkney Springs, Va.)

Morse countered that Mrs. Luce's remark was "part of an old pattern of mental instability on her part."

Though Eisenhower came to her defense, Mrs. Luce decided not to accept the ambassadorship, saying "the climate of good will was poisoned by thousands of words of extraordinarily ugly charges against my person, and distrust of the mission I was to undertake."

She wrote articles for McCall's and other magazines, and occasional newspaper commentaries. In 1964 she was an enthusiastic supporter of Sen. Barry Goldwater (R-Ariz.) for president.

By then the Luces were living in Arizona for part of each year, and it was at their Arizona residence that Henry Luce died at 69 in 1967.

A few years later Mrs. Luce moved to Honolulu where she had a house on the beach near Diamond Head, but she traveled to New York and Washington several times each year. In 1981, when Reagan's election returned conservative Republicans to power, she moved to Washington.

She was a recipient of the Medal of Freedom and was the first woman to win the U.S. Military Academy's Sylvanus Thayer Award for her support of a strong national defense.

Survivors include two stepsons, Henry R. Luce III and Peter Luce.